Conventionally, in hybrid capacitors, an electrode which applies, for example, lithium titanate as an active material for lithium adsorption and release of a negative electrode is utilized. In such hybrid capacitors, for a positive electrode material, for example, an active charcoal is applied as a carbon material which employs a porous structure or a fibrous structure with an electric double layer capacity. Those negative electrode and positive electrode are opposed to each other via, for example, a cellulosic separator therebetween to form a hybrid capacitor cell.